ants/readme.md

SWARM challenge

The plan:

• Reproduce the maps on the website
• Create an assembler to generate bytecode. Add special instructions to define tweakable params and optional code blocks?
• Create an antfarm: a high-performance program that can score ant programs inside those maps
• Create a highly modular and customizable ant program
• Create a program that makes small random changes to ant programs
• BREED SUPERANTS

Contents of this repo:

• /reference contains reference materials describing and defining the challenge
• /maps contains scripts to generate and view maps (nodejs)
• /asm Assembles antssembly into my custom antbytecode
• /farm This runs the ALIEN ANT FARM

Reference

The reference folder contains

• A sample ant program
• The reference found on the website
• A wget download of the relevant SPA

Maps

As mentioned in the reference, there are 12 map generator functions.

• chambers
• bridge
• gauntlet
• islands
• open
• brush
• prairie
• field
• pockets
• fortress
• maze
• spiral

When looking in the browser, the generated maps have names like 'chambers-3lc8x4' or 'bridge-1u7xlw' where the string after the dash is the seed used, encoded in base36.

• nodejs maps.js generate -n 120 -o mymaps.maps generates 120 maps and stores them in mymaps.maps
• nodejs maps.js view bridge-1u7xlw renders the indicated map to ascii

Asm

The assembler is not copied from the challenge, but a new implementation.

It has a couple of deviations from the spec:

• Literals can only be 0-255, non negative. This is done to simplify the bytecode somewhat. I do not believe i will need literals outside this range (famous last words). This is only the literals in the assembly. The actual registers are full 32bit.
• Constants, tags and aliases all end up in the same pool, and are case insensitive
• JMP main is always prepended to every program

The bytecode is quite simple. Every instruction is 4 bytes. The first byte is the instruction number, the other 3 are single-byte arguments.

Jump instructions are a special case. They need to specify a target instruction offset, and the conditional jumps also take two normal arguments. This does not fit into 4 bytes. To accommodate this, our cpu introduces a 9th register called JR and 2 'hidden instructions' called SJR and MJR. Any jump instruction is assembled into 2 bytecode instructions: first SJR or MJR and then the original instruction. SJR (Set JR) uses all 3 argument bytes as a single unsigned little endian int to describe the offset. MJR (Move JR) copies the value from a register into JR. The jump instructions simply use JR as the destination address

FARM

Some would say this is where the magic happens.

This is a program that reads the maps file (generated by the maps script), and an apm file (ant program, generated by the assembler) and starts breeding ants!